Multi office telephone system



April 30, 1929. w POWELL 1,710,803

MULTIOFFIGE TELEPHONE SYSTEM Filed April 15, 192' 4 Sheets-Sheet April 30, 1929. V w, POWELL 1,710,803

MULTIOFFI CE TELEPHONE SYSTEM Filed April 15. 193 4 $heets$heet 3 i l WI'H F\G Z INVENTOR \NlNFEE-D T. POWELL.

April 30, 1929. w, POWELL 1,710,803

MULTIOFFICE TELEPHONE SYSTEM Filed April 15, 192 4 Sheets-Sheet 3 E INVENTOR Ill-ill wmnzo 1-. POWELL '6' BY m- 9 W 'r'- ATTORNEY April 30, 1929.

w. T. POWELL 1,710,803

MULTIOFFICE TELEPHONE SYSTEM Filed April 15, 192 4 Sheets-Sheet 4 WlNFRLP T- Wu.

lit)

calling incoming line.

Patented Apr. 30, 1929.

UNITED STATES PATENT OFFICE.

WINFRED T. POWELL, OF ROCHESTER, NEW YORK. ASSIGNOR TO THE STBOMBERG- CARLSON TELEPHONE MANUFACTURING COMPANY, OF ROCHESTER, NEW YORK,

.A CORPORATION OF NEW YORK.

MULTI OFFICE TELEPHONE SYSTEM.

Application filed April 15, 1927.

In manual telephone systems and also in automatic telephone systcnu-i itis frequently desirable to employ baclesclecting or tinder switches in interconnecting incoming lines with certain outgoing lines or trunks. Such finder switches, while they permit the use of a minimum amount ot equipment, have the disadvantage that a call delayml during the time that the switch hunting for the k This delay may be further increased due to the fact that each finder switch. as now employeih seizes the first calling line which it reaches irrespective of the fact that other lines may have originated calls arlicr. 'llhcrcaiiter it is necessary to start asecond finder switch in operation to seize the first calling incoming line from which it will be .611 that it is possible under certain conditions for a long period of delay to intervene before the call is extended.

In accordance with the prc nt invention, it is proposed to provide what is known as a by-path arrangement by which a temporary ctmnection is extended from a calling incoming line to a trunk during the period that a finder switch is operating to extend its trunk to the calling incmning line and when this last mentioned connection is established the temporary or by-path connection is disestablished.

Another feature resides in the provision of means whereby callin; incoming lines are extended to trunks in the sequence in which they originate calls.

A further feature of the present invention is the provision in such a by-path arrangement or means common to a plurality of switches for directively operating any allotted switch to seize a predetermined calling incoming line even though its brushes pass over terminals of another incoming line.

An additional feature of the invention includes the incorporation of such a finder switching arrangement for trunking between the various oflices ot' a manual telephone system.

Referring to the drawings,

a A Figs. 1 and 9 when placed in the order named, diagrammatically represent a portion of a telephone system including a socalled A otliee and a so'called B otfice. Fig. 1 and the portion of Fig. 2 shown at the left of the broken line Serial No. 184,030.

represent a calling subscrihcrs line and an opcratofis position at an originating or A office. It will be understood, of course, that there are a plurality of subscribers lilies terminating at this ofiicc and a plurality of A. operators positions, only one of which is indicated, and associated with this position there is provided an outgoing trunk accessible to a finder switch, the operating circuits of which are represented in the right hand portion of Fig. 1 and the lefthancl portion of Fig. 2. In the broken line rectangle of Fig. 1 there are indicated the circuits of an allottcr switch which functions to allot idle finders of a group for use and also to establish a temporary or bypath connection during the time that an allotted finder switch is performing its hunting operation. At the right-hand portion of Fig. 2 there is indicated the B operators position in which one of a plurality of called lines is shown as terminating. Figs. 3 and 4 represent a modified form of the invention including A and B ofiices with telephone lines terminating at each otiice and finder switches for performing the trunking operations between these oflices. The modification represented in these last two figures difl'ers mainly from the modification first described in that it employs a difi'erent circuit arrangement for directivcly operating the finder switches.

The finder switch employed in this system may be similar to those disclosed on page 46 of Automatic Telephony by Smith and Campbell (first edit-ion), while the allotter switches may be similar to those disclosed in the patent to Clement #1,107,153 granted August 11, 1914.

W'ith this brief outline of the invention, it is believed that the modification of Figs. 1 and 2 will best be understood by describing the method of establishing a. telephone connection from a telephone line indicated at A to a telephone line indicated at B. When the SLIbSCI'lbQI removes his receiver from its swil-ch hook the line relay 10 is energized over the two sides of the calling lines in series and attracts its armature to light the line lamp 11. The A ope 'ator upon noting that this lamp is light-ed, inserts the plug P of an idle cord circuit at her position into an answering jack J of the calling telephone ill) line. This operation completes a circuitthrough. both. nilnlings oi. the answering :-=uperrisory relay l2 and the two sides ot 1c answer-hue. cord and the calling tchaphone ne also in the series. The insertion of' the plug l? into the jack J also con'ipletes a cirruit ironi grounded battery. the resistor, slccrc contacts of the plug and jack. Winding at thrcuholi relay 13 to ground. The cutotl' relay is thus energized and at its armalurrs and ('llllltlCio opens the energizing circuit o t the line relay it] which t-llQltillllOll deenerg aes to extinguish the line lamp 11.

ill: this time the A operato1."s telephone set (not shown) is connected either inanually or inrtoniatically through the cord circuit taken. :lor use to the calling telephone line so that the opcratm' 121D inquire the designation oi the wanted telephone line. Upon ohta. i this intorniation she then inserts t the 'o i tie it ck J, which is one of a group ottrd to the Wanted oilice. .l**1ch -lrs provided with an outgoing eh terminates in the terminals t and unit-selecting tinder switch, itor purposes oil this description. is assumed to be at the type known as the upaud round switch. As soon as the plug l is inserted into the jack il a circuit is closed trout grounded battery, through the c stance sleore contacts oi? the plug P and aclr -oiinling of the cut-oil relay 14, its continuity spring and back CO1 tact, back tact an arniatrue of the reay 15, to

l. last. described circuit is cond in n 1. Th is oiled i" the armature and back contact of nc r lay lo associated with the allotter snitch tor the purpose ot preventing any iulcr'lcmice between conten'iporaneons calls in case too icrator extended a connection to a second aclr similar to d before the thidcr switch hid completed its first conuiou. llr ay Ll: when operated in this closes a locking circuit for itself the sleeve contacts of plug and ack its continuity spring and arnu tarr contiuui spring and back contact of relay ll whaling of relay 1!), to ground. lielay J... iperated in this circuit and functions to start. the allotter switch in operation while it disconnects the ground connection 'lroni all other relays of this group of outgoing trunks similar to relay 1 1. \Vhen the relay 1? is energized an operating circuit s closed tor the motor magnet 17 of the al- (it l tier :lroni grounded battery, the resistor, i 1 ing. hack contact and armature 0t this n agnel. inner back contact and armature actcrizcd by the presence of ground potential. At this tune the test relay l8 is opcra'cd in. a circuit from grounded hatlcry. the resistor. armature and trout contact o'li rclay l5. through the low resistance winding oi" the relay 18, test hrush 23. test terminal El -l: of the idle trunlc. hack contact. and continuity spring oi" relay ill). conductor :36. vertical oilfnornnil contacts VON. hack contact and armature ot relay E27. to ground. Y energized/in this circuit and locked operated 'troin grounded battery, I'KSlSlXUlCt HI nurture and trout contact of relay 1;). high resistance winding of relay 18, its front contact and arn'uiture. front contact and ar inature of relay ll, to ground. lVith the relay l8 actuated, the switching relay 28 is operated .iroin grounded. liiattery, resistor outer armature and trout contact of relay l8 Winding o't relay 28, front contact of the sleeve relay Ll, bacl: contact and armature ot relay 1G to ground. When the relay 528 is opeated. the calling sulasci'ihefis line is extended through the A ope fators cord circuit and the outgoing trunk connected to the jack 3 to the conductors 2!) and oil the selected ilug endcd trunk terminating at the operatoids position equipment at the distant otlice which may be similar to that disclosed in the application oi. John ll. Ler's, Jr" 5. N. T2119? 5 Dec. 22 3. 1925 Patent No. hGTSJKSS oi July 524:, 1928.

The A ope 'ator may then instruct the P) opera or as to the inunhcr of the wanted line and the B operator may proceed to coin ncct the plug P of this trunk into the jaelr J of the called telephone line and thereafter actuate ringing equipment (not shown) to signal thi telephone-line. It will be noted that the make-busy relay 27 has its righthand winding bridged arrow; the tip and ring conductors 29 and 30 ol. the selected primary trunk which receives its source of battery through the windings of the calling supervisory relay 31 0t Fig. 1. Relay operates and at its right-hand continuity spring and arnuitnrc opens its original encn gluing circuit but sulr-ititutes a holding circuit tor itscl't 'liOlll ground through its lefthand winding, coinluctor 2th upper continuity spring and baclr contact ot rclzrr iifl. terminal and allotter lJlIlSl'l 23, right-- hand winding ot relay l8, right-hand trout contact and in'nniluri-z of relay 15 the resistor, to grounded battery. The operation of relay 2? removes the direct ground from conductor 26 at its left-hand back contact and armature so that this trunk cannot be seized. by another allotter switch.

As soon as the relay 97 is operated. it starts the operation. of the allotted tinder switch by closing a circuit from ground left-hand arniatiu'c and front contact oi relay 27, conductor inner armature and bacl: Contact of relay 25, winding of relay llelar 18 is till ill)

333. its continuity spring and back contact, through the contacts 34, known as the pickup contacts of a common impulse machine, and thence through the resistor to grounded battery. Itwill be understood that the pickup contacts Eli are provided so that the common impulse machine will be inetlective to control the tinder switch until the impulse machine is at the beginning of a cycleor series of impulses. \Vhen the contacts 3st are closed, the relay 33 is operated and closes a holding circuit for itself indimendcntly oi oi the pick-up contacts. which circuit is similar to that previously described except that it now extends through the continuity spring and armature of the relay 38, and resistor to grounded battery. As soon as the pick-up relay 33 operated it closes a circuit for impulse relay 36 from grounded battery, winding of this relay, left-hand lront contact and armature oil pick-up relay 33, armature and back contact of changeover relay 37, conductor 38, allotter brush l9, uppermost front contact and armature of relay 38, conductor 38, allotter brush l9, uppermost front contact and arniature of relay 28, conductor 39 contacts 1H) of the #3 interrupter, sinceit is assumed that the call ing outgoing trunk is in the third group and. thence from the contacts of this interrupter to ground Under the control of this circuit the impulse relay 36 of Fig. 2 receives three group impulses as a result of which an operating circuit is closed for the primary motor magnet 41 from grounded battery, wind ing of this magnet, back contact and armature of change'orer relay 37, front contact and armature of impulse relay 36 to grouiul. The primary motor magnet thus operated to advance the brushes 42, ill and ell, three steps in their primary or groupselecting movement.

The con'unon interrupter continues to rotatoand when the pick-up contacts 3 are again closed, at the conclusion of the send ing of the series of group impulses, the change-over relay 37 operated in a cir cnit now extending from grtninded battery, the resistor, interrupter contacts in back contact and continuity spring of the relay 37, its winding, off-normal contacts 45 which are closed as soon as the switch begins its group-selecting movement, back contact and armature of relay E25, conductor 3:2, front contact and armature of relay 27 to ground. The change-overrelay on operation closes a locking circuit for itself from grounded battery. the resistor 35, its armature, continuity spring and winding, and thence to ground over the remainder of the circuit previously described as extending through the vertical ott-nornnil contacts 415. The tinder switch now in readiness to receive the units-se leeting impulses and since it is assumed that the designation of the outgoing trunk is No. 35, the connnon impulse machine is connected in such a manner that the finder switch receives five directive nnpulscs from the impulse relay 36. These impulses are generated in a circuit now traceable from grounded battery, winding of impulse relay 36, front contact and armature of relay 33, right-hand armature and front contact of the cl1a11gcovc1 relay 37. conductor 16,111- lotter brush 20, front contact and armature l? of relay 28. impulse contacts 48 of the common impulse machine, to ground. Under the control of this circuit the impulse relay 36 generates five impulses and in re sponse to each of these impulses the secondary motor magnet 49 is operated from grounded battery, its winding, outer left hand front contact and armature of relay 37, front contact and armature of relay 36, to ground. I11 response to each of these 1111- pulses the brushes i2, 43 and 4st of the tinder switch are advanced five steps in the selected group which movement positions these brushes in engagement with the terminals of the outgoing trunk terminating in the jack J hen the pick-up contacts EM are again closed at the conclusion of the units series of impulses, the switching relay is 'operatcd in a circuit traceable from grounded battery, the resistor, pick-up contactsild, outer left-hand contact and armature of relay 37, upper winding of relay 25, rotary ott-normal contacts 50, closed on the first rotary movement of the switch, to ground. The operation of the switching relay ex tends the outgoing trunk through the brushes l2 and 43 of thctindcr switch to the conductors 29 and of the trunk terminating at the selected B operato1"s position. As soon as the relay 2:") is energized it also closes a locking circuit for itself from grounded battery, its lower winding, its in .ncrmost front contact and armature, lefthand front contact and armature of relay 27 to ground. At the continuity spring and contact oi? the switching relay 2:) the circuit, which has been guarding the testconductor of the allotter from interference by other allottcrs testing this trunk, is opened but this trunk is still retained for use in a guarding circuit now extending from ground, left hand winding of the make-busy relay 2?, conductor 26, continuity spring and armature of the relay 25, test brush ll of the findcr, outer armature and front contact of sleeve relay lit. and winding of relay 16 to grounded battery. The n1ake-busy relay 27 is thus held operated and the relay 113 is energized for a purpose to be described. At

the innermost back contact and armature of the switching relay 25 the holding circuit of the (:l1:111gco\c1.' relay 3? and the pickup relay 33 opened to cause these relays to deenergize. \Vith the switching relay thus ltlt) ill Civ

to disconnect the allotter tor use in establishing another connect-ion. On the opera tion of the relay 16, the cut-oil relay 14: is locked operated directly to ground through its continuity spring and armature and through the continuity spring and armature of relay 16 instead of to ground through the winding of the relay 15. It will now he noted that the make-husy relay 2? is controlled hy the sleeve relay 1% which in turn is con trolled at the sleeve contacts of the plug P and acl: J and that the. switching relay 25 is maintained energized from a make conta 'tof the make-busy relay.

At the conclusion of the conversation, supervisory equipment (not shown) signals the B ope 'ator who thereupon removes the plug P from the jack J of the *alled line. Other supervisory equipment at the A operators position also gives a disconnect signal to this operator who thereupon removes the plug P from the jack J and also removes plug P from the jack J When the plug i is disconnected from the jack J the cutott' relay ll: deenergizes, which relay at its outer armature and contact opens the holding circuit of the relay 16 causing it to deenergize. This holding circuit of the relay 1th it will he remembered, included the lefthand winding of the make-busy relay 27 of Fig. 9 also deenergizes and thereby completes a circuit; for the release magnet 51 liroln grounded hattery, winding of this magct; vertical otl'ann'nial contacts 52, hach conact and armature of relay 27 to ground. The release magnet on operation restores the tinder switch to its normal position in the well-lmmvn manner and thereby opens the otlT-norinal contacts f2. At this time also ground. potential. is connected to the test conductor of this last-used trunk through the left-hand arn'iature and hack contact of mahe-husy relay 27 and the vertical oili'iormal contacts so that this trunk is again in. condition for use.

The modification shown in Figs. 3 and 4, shows a different auangement tor directively operating the finder switches. The present inodification, however, shows an. arrangenn-nitby which a. conventional upand-arouml switch, normally having access to one hundred outlets, may he arranged to hawv access to a greater numher of trunks. In Figs. 3 and 4 two otticcs are indicated hut it will he understood that this is merely for purposes of description since the system may have many more ofiiees. In this arrange nient when a calliin suhscriher at- C initiates a call, his line relay is energized to light the line lamp and the A operator inserts the plug P into the jack d. This operation completes an energizing circuit tor the cutotl' relay which causes the line relay to deeuergize in turn extinguishing the line lamp 5st. The A opcritofs telephone set (not shown) is then connected to the cord circuit taken tor use and she inquires the numher of the wanted line which it is assumed is the line 1) terminating at the li c'ill'ice shown at the right ot Fig. -l. The operator then inserts the illllllg plug l. into the pick J" which is elicctive to energize the cutotl relay 56 from grounded hat tery, the resistor, sleeve contacts off this plug and jarlu winding oi? the relay 56, its continuity spring and lack contact, conductor h? hack contact and armature oil the relay 5b, to ground. lit no othe "allotter associated with this group of outgoing trunks is in use the relay will he in its normal position and this last descrihcd. circuit is ctt'ective to operate the sleeve relay ot' the cord and the cut otif relay 56 oil? the trunk. Relay so when operated closes a locking circuit or itselil through its continuity spring and armature, continuity spring and hack contact of the relay 9, conductor (it) winding of the relay 58, to ground. The cut-oll relay is thus held operated and the relay 5a is energized to remove the ground potential from all other cut-o'tl' relays such as at; of this group at the ope 'ators section so that it any other ope aim at this section connects one o'lf her cord circuits to an outlet iacl; similar to J of this group. the outgoing trunk connected thereto will not seize the allottcr until. the connection first initiated has heen cone pleted to the selected trunk througvzh its associated tinder switch The energization ot the relay 53S closes an operating circuit for the motorinagnct (ll of the allotter from grouni'lcd hattery, the resistor, winding hack contact and armature of this magnet, hacl: (.m'itact and ari'nai'ure of relay 62, front contact and armature of relay 58, to ground. Under the control of this circuit whirl self-interimited. the motor magnet ad *anccs the hrusl es: 1'32", (it, and (16 of the allotter until the test luush encounters the test terminal oi" an idle trunk which charactericaed, hy the presence of direct ground potential. The energization of the relay 58 also completes a portion of the test circuit for the allotter which is traceahle from grounded hattery. resistor. right-hand. armatu e and l'ront contact of: relay 5S, right-hand low resii-daiu-e winding of the switching relay 0:2 and thence to the test hrush (35. The motor magnet :ulvanres the brushes ot the allot'ter until its test hrush encounters a test terminal. characterized by the presence of direct ground potential thercon, at which time the mentioned testing circuit including the right-hand winding of the switching relay 62 is completed over condue-tor 63 of the idle trunk, oti normal contacts 161i, inner back contact and armature of the makc-busy relay 65, to ground. The switching relay 62 is energized in this circuit and at its left-hand armature and back contact opens the operating circuit for the motor magnet 61 to stop the allot-tor switch while at the left-hand front contact and armature of relay 58 there is closed a locking circuit from ground through the left-hand arn'iature and front contact of the relay 62, its high resistance Winding, right-hand contact and armature of relay 58, resistor to grounded battery. The operation of the re lay 62 closes an energizing circuit for the switching relay 67 of Fig. 3 from grounded lfa'ittcry, the resistor, continuity spring and back contact of relay 59, outer armature and front contact of relay 56, winding of the slow releasing switching relay 67, conductor (38, inner front contact and. armature of relay 32 to ground. The switching relay 6'? when thus energized connects the outgoing trunk jack J through the brushes (it; and (S4 of the allotler to the tip and ring conductors 69 and 70 of the trunk terminating at a B (me/rations position in the wanted ofllce. \Vith the outgoing trunk extended in this manner, a circuit is completed from ground and. grounded battery through the windings of the supervisory relay 7.]. of Fig. 3 and thence through the tip and ring comiluctors 69 and '70, upper winding of the relay 1%, its continuity spring and back contact. Relay 1.6:") is actuated in this manner and is held operated from ground through its lower winding, conductor 63, allotter brush 65, through the low resistance winding of the relay (52, front contact and armature of the relay 5S, and the resistor, to grounded bat tery. The operation of the make-busy relay 105 renders the trunk selected by the allotter unselectable because it removes the direct ground potential normally connected to the test terminal thereof.

The A operator may then transmit the designation of the wanted telephone line over this temporary connection to the trunk including conductors 69 and T0 with which there associated at the B operators position a B operator's telephone set well as signaling and supervisory equipment, (notshown).

The B operator upon receiving designation of the wanted line inserts the plug P into the jack J thereof and signals the subscriber in, the well-known manner. In the event that no other finder switch of this group is being operated to locate an outgoing trunk then the operation of the make busy relay 165 is effective to startthe operation ofthe finder switch of Fig. 4. This operation is initiated by the closure of a circuit from ground, inner armature and front contact of relay 165, inner armature and back contact oi the relay 72, winding of the Slow releasing relay 73, its continuity spring and back contact, armature and back contact of relay 7%, resistor to grounded battery. The relay '73 is energized in this circuit and closes a locking circuit for itself from grounded battery, winding of the relay 7+1, armature and continuity spring of relay 73 and thence to ground, over the remainder o the circuit previously described. The relay 74: is common to all of the trunks of this group and when it attracts its arniaturcs it disables the starting circuits of all the other finder switches of the trunks to which itis common. It will readily be understood that if the other tinder switches of this group were not disabled and some other tinder switch were permitted to start operation, it would be possible for the first call to be dc layed since the finder switch first started might seize a later call.

With the relay 73 operated as just described, a driving circuit for the primary motor magnet 75 is closed from gmmnded battery, through the resistor, winding of this magnet, its inner back contact and armature, inner back contact and armature of relay 76, front contact and armature of the relay 73, to ground. Under the control of this circuit idle primary motor magnet advances the brushes 77 to 82 inclusive and the group brush 83 of the switch until the group or level brush 83 encounters the group or level corresponding to contact Bl in which the outgoing trunk terminals are located. When this group terminal 8:4: is found the switching relay85 is actuated in a circuit traceable from grounded battery, through the resistor, outer back contact and armature of the primary magnet 75, outer back con: tact and armature of the relay 76, outer front contact and armature of relay 73, winding of the switching relay 85, group brush 83, group terminal 84, conductor 86, inner front contact and armature of the relay 67 to ground. As soon the switching relay 85 is thus operated it closes an energizing circuit for the change-over relay 76 completed from grounded battery, winding of the relay 76, front contact and armature of relay 85, to ground. The change-over relay 76 upon attracting its armatures closes a locking circuit for itself through its inner left-hand front contact and armature, oiinormal contacts ON, to ground, and also completes a driving circuit for the secondary motor magnet 87 from grounded battery, through the resistor, winding of this mag net, its back contact and inner armature, right-hand front contact and armature of relay T6, inner front contact and armature of the relay 73, to ground. This driving iii) :iitii'iii' cams-10s Hm Sflfliltiflifl" 11101701 magnet '0 :iilivpnue the imwiws W to S2 inciui-iivv of he 'inihir switch in iii: 50001111111 nuJveiuc-mt over: Hm terminals 0:1? the smioui'aiii group. fiincu ii:- is nssmnuei at this time that Hm rainy S8 i4 not cnei 'imd, only Hi0 iiii'iiihi -s to 8:; i wzliisi'm of the iinijiul, iMVifiCii. are uii'uctive. ii iimi Hi1: text brim-11 SO (TE the filldijl ell l zigcs The test ioiminui (if HM: mu egoing ii-iiiilr imtminniing in the junk J i'he ;--;i0; )in;; magnet 58) of Fig. 3 is :zi-i uzii'izii. in a (.tiIfLCLLiii cnmpieiwi. f1 J; gmuml through. Him 10W ]'U;3i'j110! winding if]? this: rainy, miter t'fllllili'liiif and hunt cmit'iicii 0f the ii 89,1051 toi'iiiiimi 90. ii .t

brush 80, letii'fiizmii L wk contact :11 (i numb tum m Hm rviaiy 881 ammturu :1 mi ")ili iron tact 0i Hm r9123 Ti) upper win-ling; of Him mini T2 ou'fm. bu Elie 111" :0 of H19 vmiiiliuiiiii: 1;?) mini "H; (ii.

this: "any (harm exists an iwcl'iappirig mil-- iiiu iii i i uiii'aiiei' mm lLiL'i'iUliviiE-l ti: vsiubiish Him iaiiiiiiimctiiiii ii iiiiiurimg the plug P mio the u J" LHHi. 111mm. signals the wanted lilil ijjwi' ii 'ii'iwimw mm iii Hm i-uiriy iniim: iniu c: immizi iv i in); M35; in; gym i Thu minding U'f this iaiiii nurt nmi iil'lllikl fii'iimi *miim'l's UN,

: 1* un air-1* (if the 1'0- 1 iiiiivi swifirh 21nd Ill) incoming lines, a plurality of outgoing lines, a finder switch for each outgoing line for connecting it to any calling incoming line, an allotter for assigning finder switches for use, means including said allotter for es tablishing a temporary by-path connection between a calling incoming line and an assigned outgoing line, and. means including an impulse device common to said switches for transmitting to said assigned finder switch a series of code impulses individual to the calling incoming line whereby said finder switch is directively operated to lind said calling incoming line to the exclusion of other calling incoming lines.

3. In a telephone system, a plurality of incoming lines, a plurality of outgoing lines, an auton'iatic finder switch for each outgoii'lg line for seizing a calling :incoming line, means including an allotter for assign in a finder switch for use and for establishing a temporary connection from said calling incoming line to the trunk of said assigned finder switch, said finder switch operating by group and unit-selecting move ments to complete its operation, and means ineluding an impulse device common to a plurality of said switches for transmitting group and unit-selecting code impulses to directively operate said assigned finder to select the calling incoming line to the ex clnsion of other calling incoming lines.

t. In a telephone system, a plurality of incoming lines, a plurality of outgoing lines, an automatic lindcr switch for each outgoing line for seizing a calling incimiing line, means including an allottcr for assigning a. finder switch for use and For cw tablishing a tempmary comiection from said calling incoming line to the trunk of said assigned finder switch, said tinder switch operating by group andunit selecting movements to complete its operation, means including an impulse device common to a plurality of said switches comprising a plurality ol impulse circuit interrupting mechanisms for transmitting group and unit selecting code impulses to di rectively operate said assigned tinder switch to select the calling incoming line to the exclusion of other calling incoming lines.

5. In a telephone system, an A operator-s position, a plurality of incoming lines terminating thereat, telephone lines terminating at said A operators position, means for interconnecting a calling telephone line and an incoming line, a B operators position,

trunks terminating at said B operators osition, means including an automatic finc or switch for each trunk for connecting said trunk to a calling incoming line, and operating means for said automatic switch functioning to cause said automatic switch to seize said calling incoming line to the. exclusion of other incoming lines calling at the same time.

6. In a telephone system, an A operators position, incoming lines extending therefrom, a B operators position, trunks terminating thereat, an automatic switch for each trunk for extending said trunk to a calling incoming line, means responsive to the initiation of a call on one of said incoming lines for establishing a temporary connection therefrom to an idle trunk, and means for operating the automatic switch of said trunk to seize said calling incoming line to the exclusion of other calling incoming lines to replace said temporary connection. 7

7. In a telephone system, an A operators posit-ion, incoming lines extending there from, a B operators position, trunks terminating in said last-mentioned position, an automatic switch for each trunk to connect it to a calling incoming line, an allotter for assigning idle automatic switches and associated trunks for use, means responsive to the initiation of a call on one of said lines for extending said line through the brushes of said allotter to the assigned trunk, and common impulse mechanism for directivi-ily advancing the automatic switch of said trunk to seize the calling incoming line.

8. In a telephone system, an A operators position, incoming lines from said position a B operators posit-ion, trunks terminating at said last mentioned position, an automatic switch for each trunk operating to connect a calling incoming line to an idle trunk, an allotter for assigning an automatic switch and its associated trunk for use in extending a connection, means responsive to the initiation of a call onany one of said incoming lines for extending said line temporarily through the brushes of said allotter to the allotted trunk, means including circuits extending through brushes of said allottcr for directively operating the allotted automatic switch to seize the calling incoming line, and means for releasing said temporary connection. a

In witness whereof, I hereunto subscribe my name this 5th day of April A. D. 1927.

WINFRED T. POWELL.

(ill 

